Automotive seat track having vertically adjustable bearings

ABSTRACT

A seat track assembly ( 10 ) is adapted to mount a seat to a floor of an automotive vehicle and provide selective forward and rearward adjustment of the seat relative to the floor among a plurality of seating positions. The seat track assembly includes an inner track ( 20 ) fixedly secured to the floor of the vehicle. The inner track ( 20 ) has a flattened bearing surface ( 37, 38 ) extending longitudinally along the inner track. An outer track ( 40 ) is fixedly secured to the seat and slidably coupled to the inner track ( 20 ) to allow selective sliding adjustment of the seat relative to the floor of the vehicle. The outer track ( 40 ) includes an arcuate bearing surface ( 57, 59 ) extending longitudinally along the outer track ( 40 ) and opposing the flattened bearing surface ( 37, 38 ). A plurality of cylindrical bearings ( 80 ) are positioned between the flattened bearing surface ( 37, 38 ) of the inner track ( 20 ) and the arcuate bearing surface ( 57, 59 ) of the outer track ( 40 ) to accommodate torsional loading and movement of the outer track with respect to the inner track while facilitating the selective sliding adjustment of the seat relative to the floor.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a seat track assembly for interconnecting aseat to a floor of an automotive vehicle and, more particularly, to flatand arcuate bearing surfaces within the seat track assembly allowingtorsional loading and movement of a mobile outer track relative to afixed inner track.

2. Description of the Related Art

Automotive vehicles include seats for supporting occupants within thevehicle. Seats typically include a seat track assembly interconnectingthe seat to a floor of the vehicle to allow selective locking andadjustment of the seat along the floor of the vehicle among a pluralityof seating positions. A seat track assembly includes a fixed trackfixedly secured to the floor of the vehicle and a mobile track slidablycoupled to the fixed track and fixedly secured to the bottom of theseat.

It is known to provide a plurality of bearings between the fixed andmobile tracks to reduce friction and facilitate movement of the mobiletrack relative to the fixed track. An example of a seat track assemblyusing such a plurality of bearings is disclosed in the U.S. Pat. No.5,741,000, which issued to Goodbred on Apr. 21, 1998.

It remains desirable to provide a seat track assembly having a pluralityof bearings that allows torsional loading and movement of the mobiletrack relative to the fixed track while, at the same time, facilitatingsliding movement of the mobile track relative to the fixed track.

SUMMARY OF THE INVENTION

According to one aspect of the invention, a seat track assembly isadapted to mount a seat to a floor of an automotive vehicle and provideselective forward and rearward adjustment of the seat relative to thefloor among a plurality of seating positions. The seat track assemblyincludes an inner track fixedly secured to the floor of the vehicle. Theinner track has a flattened bearing surface extending longitudinallyalong the inner track. An outer track is fixedly secured to the seat andslidably coupled to the inner track to allow selective slidingadjustment of the seat relative to the floor of the vehicle. The outertrack includes an arcuate bearing surface extending longitudinally alongthe outer track and opposing the flattened bearing surface. A pluralityof cylindrical bearings are positioned between the flattened bearingsurface of the inner track and the arcuate bearing surface of the outertrack to accommodate torsional loading and movement of the outer trackwith respect to the inner track while facilitating the selective slidingadjustment of the seat relative to the floor.

BRIEF DESCRIPTION OF THE DRAWINGS

Advantages of the invention will be readily appreciated as the samebecomes better understood by reference to the following detaileddescription when considered in connection with the accompanying drawingswherein:

FIG. 1 is a section view of a seat track assembly incorporating oneembodiment of the invention therein; and

FIG. 2 is a fragmentary side view of the seat track assembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, a seat track assembly of the invention is generallyshown at 10. A pair of seat track assemblies 10 (one shown) slidablyinterconnects a vehicle seat 12 to a floor of an automotive vehicle. Theseat track assembly 10 allows selective forward and rearward adjustmentof the seat 12 among a plurality of seating positions along the floor ofthe vehicle. The seat track assembly 10 includes a latch mechanism 16for selectively locking the seat 12 in any one of the plurality ofseating positions. An example of a latch mechanism 16 is disclosed inPCT Application US01/44685, which is hereby expressly incorporatedherein by reference in its entirety.

The seat track assembly 10 includes a fixed or inner track 20. A riser14 interconnects the inner track 20 to the floor of the vehicle. Theinner track 20 has a generally U-shaped cross-section defined bygenerally parallel upright sides 22, 24 each having first 26, 28 anddistal second 30, 32 ends. A base 33 extends laterally between the firstends 26, 28 of the sides 22, 24. An outer edge 31 extends laterallyoutwardly from each of the sides 22, 24. A generally flat bearingsurface 37, 38 is formed in the outer edge 31 and extends longitudinallywith respect to the inner track 20. An outer wall 35 extends generallyperpendicularly from each of the outer edges 31 to define a flange 34,36. A plurality of teeth 39 is formed along at least one of the outerwalls 35. The plurality of teeth 39 is disposed longitudinally withrespect to the inner track 20 for cooperating with the latch mechanism16 to define the plurality of seating positions. Each bearing surface37, 38 extends longitudinally between spaced apart tabs 41, 43.

A mobile or outer track 40 is fixedly secured to the seat and slidablycoupled to the inner track 20. The outer track 40 includes generallyupright sides 42, 44 each extending between a first end 46, 48 and adistal second end 50, 52. A base 54 extends laterally between the firstends 46, 48 of the sides 42, 44 of the outer track 40 to define aU-shaped cross section. Concavities 56, 58 are formed in the base 54 ofthe outer track 40 corresponding to the flat bearing surfaces 37, 38 ofthe inner track 20. Each concavity 56, 58 protrudes toward the innertrack 20 to define an arcuate bearing surface 57, 59 opposing thecorresponding flat bearing surfaces 37, 38. Each arcuate bearing surface57, 59 extends longitudinally with respect to the outer track 40. Eachsecond end 50, 52 of the upright sides 42, 44 of the outer track 40includes a hook 60, 62 engaged With the flanges 34, 36 of the innertrack 20 to prevent vertical separation of the outer track 40 from theinner track 20. A plurality of spacers 64 extends over each of the hooks60, 62 between the inner 20 and outer 40 tracks to reduce rattle betweenthe inner 20 and outer 40 tracks.

Referring to FIG. 2, the latch mechanism 16 is operatively coupled tothe outer track 40. The latch mechanism 16 includes a latch plate 74having a plurality of apertures 79 for lockingly engaging the pluralityof teeth 39. While engaged with the plurality of teeth 39, the latchplate 74 prevents sliding movement of the outer track 40 relative to theinner track 20. The latch plate 74 is movably supported on the outertrack 40 for movement between a locked condition, wherein the pluralityof apertures 79 is engaged with the plurality of teeth 39, and anunlocked condition, wherein the plurality of apertures 79 is disengagedwith the plurality of teeth 39 to allow sliding movement of the outertrack 40 relative to the inner track 20. A biasing member or spring 76is energized between the outer track 40 and the latch plate 74 forbiasing the latch plate 74 toward the locked condition. A release lever78 is operatively coupled to the latch plate 74 for facilitatingmovement of the latch plate 74 between the locked and unlockedconditions.

A plurality of cylindrical bearings 80 are positioned between the flat37, 38 and arcuate 57, 59 bearing surfaces to reduce friction betweenthe inner 20 and outer 40 tracks. Each of the plurality of cylindricalbearings 80 is disposed laterally with respect to the flat 37, 38 andarcuate 57, 59 bearing surfaces. Engagement between each of theplurality of bearings 80 and the flat bearing surfaces 37, 38 is definedby a line of contact extending laterally with respect to thelongitudinal extent of the inner 20 and outer 40 tracks. Engagementbetween each of the plurality of bearings 80 and the arcuate bearingsurface 57, 59 is defined by a point of contact. The line and point ofcontact between each of the plurality of bearings 80 and the flat 37, 38and arcuate 57, 59 bearing surfaces, respectively, allows for torsionalloading or movement of the outer track 40 with respect to the innertrack 20 while still permitting and facilitating sliding movement of theouter track 40 relative to the inner track 20.

A bearing guide 88, 90 extends between each outer edge 31 of the innertrack 20 and each concavity 56, 58 of the outer track 40. Each bearingguide 88, 90 includes spaced apart sides 92, 94 and a cross member 96extending laterally between the sides 92, 94 to define a generallyH-shaped cross section. Each of the plurality of bearings 80 arerotatably coupled to the sides 92, 94 of the respective bearing guide88. Each of the sides 92, 94 includes opposite bent ends 100 and 102adapted to engage the outer edge 31 and the concavities 56, 58 tolaterally retain the plurality of bearings 80 between the flat 37, 38and arcuate 57, 59 bearing surfaces.

In use, the latch plate 74 is moved to the unlocked condition to allowsliding movement of the outer track 40 relative to the inner track 20,and in turn, the seat relative to the floor of the vehicle among theplurality of seating positions. The plurality of bearings 80 rollbetween the flat 37, 38 and arcuate 57, 59 bearing surfaces to reducefriction between the outer 40 and inner 20 tracks. At the same time, thepoint of contact between the arcuate bearing surface 57, 59 and theplurality of bearings 80 allows the outer track 40 to roll laterallyabout the point of contact when the outer track 40 is torsionally loadedor moved with respect to the inner track 20 due to forces associatedwith, for example, the shifting weight of the occupant or the seatduring lateral accelerations of the vehicle or during installation ofthe lower track 20 to the floor of the vehicle when the dimensions ofthe floor fall outside anticipated design tolerances. Additionally, thelateral line of contact between the plurality of bearings and the flatbearing surface 37, 38 laterally stabilizes the plurality of bearings 80with respect to flat bearing surface 37, 38. When the seat is adjustedto the desired one of the plurality of seating positions, the latchplate 74 is allowed to return to the locked condition under the bias ofthe spring 76.

The invention has been described in an illustrative manner, and it is tobe understood that the terminology, which has been used, is intended tobe in the nature of words of description rather than of limitation.

Many modification and variations of the present invention are possiblein light of the above teachings. It is, therefore, to be understood thatwithin the scope of the appended claims, the invention may be practicedother than as specifically described.

1. A seat track assembly adapted to mount a seat to a floor of anautomotive vehicle and provide selective forward and rearward adjustmentof the seat relative to the floor among a plurality of seatingpositions, said seat track assembly comprising: an inner track fixedlysecured to the floor of the vehicle and having a flattened bearingsurface extending longitudinally along said inner track; an outer trackfixedly secured to the seat and slidably coupled to said inner track toallow selective sliding adjustment of the seat relative to the floor ofthe vehicle, said outer track including an arcuate bearing surfaceextending longitudinally along said outer track and opposing saidflattened bearing surface; and a plurality of cylindrical bearingspositioned between said flattened bearing surface of said inner trackand said arcuate bearing surface of said outer track to accommodatetorsional loading and movement of said outer track with respect to saidinner track while facilitating said selective sliding adjustment of theseat relative to the floor.
 2. A seat track assembly as set forth inclaim 1 wherein said inner track includes two upright sides and a crossmember extending laterally therebetween to define a U-shaped channel,said sides each having a distal end opposite said cross member.
 3. Aseat track assembly as set forth in claim 2 wherein said inner trackincludes an outer edge extending laterally outwardly from each of saiddistal ends of each of said sides.
 4. A seat track assembly as set forthin claim 3 wherein said flattened bearing surface is formed in saidouter edge and extends longitudinally with respect to said inner track.5. A seat track assembly as set forth in claim 4 wherein said innertrack includes an outer wall extending perpendicularly from each of saidouter edges to define a flange.
 6. A seat track assembly as set forth inclaim 5 wherein said inner track includes a plurality of teeth formedalong said outer wall, each of said plurality of teeth disposedlongitudinally with respect to said inner track to define each of theplurality of seating positions.
 7. A seat track assembly as set forth inclaim 6 wherein said outer track includes two upright sides and a baseextending laterally between said. sides to define a U-shaped crosssection, said sides of said outer track each including a distal end. 8.A seat track assembly as set forth in claim 7 wherein said base of saidouter track includes a concavity formed therein, said concavityprotruding toward said inner track to define said arcuate bearingsurface opposing said flattened bearing surface.
 9. A seat trackassembly as set forth in claim 8 wherein said outer track includes ahook formed on each of distal ends of said sides of said outer track,said hook engaged with said flange of said inner track to preventvertical separation of said outer track from said inner track.
 10. Aseat track assembly as set forth in claim 9 including a spacer extendingover said hook between said outer track and said inner track forreducing rattle between said outer track and said inner track.
 11. Aseat track assembly as set forth in claim 10 including a bearing guidefor retaining said plurality of bearings between said arcuate andflattened bearing surfaces.
 12. A seat track assembly as set forth inclaim 11 including a latch mechanism operatively coupled to said outertrack and lockingly engagable with said plurality of teeth of said innertrack to selectively lock the seat in one of the plurality of seatingpositions.
 13. A seat track assembly as set forth in claim 12 whereinsaid latch mechanism includes a latch plate having a plurality ofapertures for lockingly engaging said plurality of teeth to preventsliding movement of said outer track relative to said inner track, saidlatch plate movably supported on said outer track for movement between alocked position, wherein said plurality of apertures are engaged withsaid plurality of teeth, and an unlocked position, wherein saidplurality of apertures are disengaged with said plurality of teeth toallow sliding movement of said outer track relative to said lower track.14. A seat track assembly as set forth in claim 13 including a springenergized between said outer track and said latch plate for biasing saidlatch plate toward said locked position.